Facebook and Twitter have made sharing things - like pictures, news, and even thoughts - extremely efficient. A San Francisco start-up co-founded by former Sun Microsystems CEO Jonathan Schwartz is applying similar technology toward helping caregivers of seniors and special needs children to meet their family's needs.

CareZone is today announcing an update to its ‘freemium' service today that can simultaneously deliver voice messages to a call list of up to 100 people, adds a shared calendar to coordinate care activities, and a native iPhone application for remote access to information such as medication lists or stored documents.

Schwartz co-founded CareZone with Apple veteran Walter Smith in early 2012. Schwartz has two special needs children, and his brother does as well, he revealed. The company raised US$13 million in March from Catamount Ventures, New Enterprise Associates; Schwartz also chipped in with his own capital.

"There's lots of information to manage and no good place to do so," Schwartz said. "That was the motivation for Walter and I to sit down and think thought a service to meet our own family needs."

Its features include a profile of the person who is being cared for, a journal for sharing group notes, a private diary, a contact manager, cloud file storage, to-do lists, and notes. CareZone is looking into integrating with some specialized medical devices, Schwartz said. It may open up a programming interface for developers.

The CareZone site is free of advertising due to its inherent privacy considerations, and there is no cost for up to 5 people being cared for by a single caregiver. Beyond that, it is priced around $50 per year, and CareZone has established a professional pricing model for institutions.